In the current range your options are through one of the surround processors (G61R, G68, 861) or through the 808 CD player (the new 808.3).

There were other options in older series (a two channel digital pre-amp, the 562?) and the earlier surround processors.

M Explorer2 / Raspberry Pi / Roon
M 502
Power amp TBC
Technics SL-1210 Mk 2 / SME 309 / Denon DL-304
Pioneer BDP-450
Yamaha RX-V1067 (processing, centre, rear)
B&W 804s, HTM4s, CDM CNT
Panasonic PT-AT6000 projector